Decomposition natural bond orbitals

Most recently, Glendening and Streitwicser have decomposed the interaction energy of the water dimer using natural bond orbitals. Their natural energy decomposition analysis (NEDA) combines the normal electrostatic and exchange energies into a single ES term,... 

Decomposition of interaction energies is desired for qualitative chemical analyses of complicated multi-valent interactions in supramolecular aggregates but such a decomposition cannot be uniquely defined within fundamental physical theory. A popular semi-quantitative decomposition method with nice formal features to be mentioned in this context is Weinhold s natural bond orbital (NBO) approach to intermolecular interactions [232, 233]. Comparable is the recently proposed energy decomposition analysis by Mo, Gao and Peyerimhoff [234, 235] which is based on a block-localized wave function. Other energy decomposition schemes proposed are the energy decomposition analysis (EDA) by Kitaura and Morokuma [236] and a similar scheme by Ziegler and Rauk [237]. 

The metal-metal separations in a/p-TcClj are similar to those observed in a number of dinuclear technetium(ll) complexes (vide supra) and are consistent with the presence of a metal - metal triple bond. Further quantification of the metal-metal bonding is provided by first-principles calculations of the natural bond orbital (NBO) occupancy of the Tc-Tc bond these results indicate an NBO of 5.30, which is close to the value expected for a perfect triple bond (i.e., 6.00). In a/p-TcClj, the TcsTc triple bond should exhibit the a ic 8 8 configuration, which is also consistent with the experimental diamagnetism of the compound. Technetium dichloride crystals are stable in air and can be kept for a year without any evidence of decomposition. The p-TcCl needles are insoluble in common organic solvents and aqueous HCl at ambient temperature. No reactions occur between TcCl powder and neat PMe,. The compound disproportionates to Tc metal and TcCl. in a sealed tube at or above 600 °C [69]. 

HONDO = bond orbital - neglect of differential overlap (SCF-MO) GIAO = gauge-including atomic orbital L = Lewis-type (or localized) LC-BO = linear combination of bond orbitals LCNBO = linear combination of NBOs LMO = localized molecular orbital MSPNBO = maximum spin-paired NBO NBBP = natural bond-bond polarizability NBO = natural bond orbital NCS = natural chemical shielding NEDA = natural energy decomposition analysis NHO = natural hybrid orbital NL = non-Lewis-type (or... 

Atomic charges and orbital populations has been computed by means of Natural Bond Orbital analysis [29]. In order to estimate quantitatively the importance of ligand —> metal a-donation and metal —> ligand 7r-back-donation to interaction energies, we used the Charge Decomposition Analysis (CDA) [30] method of Frenking and coworkers [30] as implemented in the AOMIX program [31, 32]. 

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